1 This publication presents selected summary information across a range of social dimensions for Indigenous Australians, compiled from the 2002 National Aboriginal and Torres Strait Islander Social Survey (NATSISS). This Australian Bureau of Statistics (ABS) survey collected information about personal and household characteristics for Aboriginal and Torres Strait Islander persons aged 15 years or over living in private dwellings throughout remote and non-remote areas of Australia, from August 2002 to April 2003. Estimates include data for remote and non-remote areas at a national level, and for states and territories.

2 Throughout this publication, the term 'Indigenous' refers to all persons identified as being of Aboriginal, Torres Strait Islander, or both Aboriginal and Torres Strait Islander origin. Information presented on Aboriginal persons includes data on persons identified as having both Aboriginal and Torres Strait Islander origin. Similarly, information on Torres Strait Islanders also includes persons identified as having both Aboriginal and Torres Strait Islander origin.

3 While the primary focus of this publication is on results from the 2002 NATSISS, relevant data comparisons are also made between this survey and both the 1994 National Aboriginal and Torres Strait Islander Survey (NATSIS) and the 2002 General Social Survey (GSS).

4 The 2002 NATSISS collected data on a range of social dimensions from each respondent both for analysis of each of these dimensions as well as to enable analysis of the interrelationships in social circumstances and outcomes experienced by that individual. The next NATSISS (currently planned for 2008) is expected to include information for most of the dimensions covered in 2002, and for many of the topics and data items covered within those dimensions. However, some content flexibility should allow new topics to be included.

DIMENSIONS AND TOPICS INCLUDED IN THE 2002 NATSISS

5 The survey content was determined through a widespread consultation process between Aboriginal and Torres Strait Islander peoples, other key stakeholders and the ABS, and reflects Indigenous cultural values and priorities.

Law and justice - including victimisation; contact with police; and use of legal services.

7 A full list of data items is contained in the National Aboriginal and Torres Strait Islander Social Survey: Data Reference Package, 2002 (cat. no. 4714.0.55.002) available on the ABS web site <www.abs.gov.au>.

SCOPE OF THE SURVEY

Inclusions

8 The survey included Indigenous persons aged 15 years or over who were usual residents of private dwellings in Australia. Private dwellings are houses, flats, home units and any other structures used as private places of residence at the time of the survey. Usual residents are those people who usually live in a particular dwelling and regard it as their own or main home.

9 The estimated resident Indigenous population at 31 December 2002, excluding those living in non-private dwellings, was 466,802 of whom 282,205 (60.5%) were aged 15 years or over.

10 The 2002 NATSISS was conducted in non-remote and remote areas in all states and territories of Australia.

Exclusions

11 The survey excluded visitors to private dwellings. Those visitors who were a usual resident of another dwelling in scope of the survey had a chance of being selected in the survey at that dwelling or, if not selected, would have been represented by similar persons who were selected in the survey.

12 Indigenous persons usually resident in non-private dwellings such as hotels, motels, hostels, hospitals, short-stay caravan parks, prisons and other correctional facilities were also excluded. At 31 December 2002, there were an estimated 19,320 Indigenous persons (4%) living in non-private dwellings throughout Australia.

SURVEY DESIGN

13 The 2002 NATSISS was designed to provide reliable estimates at the national level and for each state and territory. The sample was therefore spread across the states and territories in order to produce estimates that have a relative standard error (RSE) of no greater than 20% for characteristics that are relatively common in the Indigenous population, say that at least 10% of the population would possess.

14 In addition, the Torres Strait Islander population was over-sampled in order to produce data for the Torres Strait Area and the remainder of Queensland.

15 The design of the 2002 NATSISS incorporated a sample of discrete Indigenous communities (including any out-stations associated with them) and a sample of dwellings in areas not covered by the discrete Indigenous community sample, referred to here as the 'non-community' sample. The samples for community areas and non-community areas were designed separately with each involving a multistage sampling process. In Western Australia (WA), South Australia (SA), Queensland (Qld) and the Northern Territory (NT), the sample design was different in community and non-community areas. In the remaining states and territories, however, the sample design was the same throughout, and corresponds to the method used in non-community areas in WA, SA, Qld and the NT.

16 The community sample was obtained from a random selection of discrete Indigenous communities and out-stations using a specially developed Indigenous Community Frame (ICF). The ICF was constructed using both 2001 Census counts and information collected in the 2001 Community Housing and Infrastructure Needs survey (CHINS). Most communities in the ICF were in remote (or very remote) areas. Within selected communities and out-stations a random selection of dwellings was made. Within selected dwellings, up to three Indigenous persons (15 years or over) were randomly selected to participate in the survey.

17 Dwellings in non-community areas were selected using a stratified multistage area sample. A sample of Census Collection Districts (CDs) was randomly selected with the likelihood of a CD's selection based on the number of dwellings containing Indigenous persons in the area as at the 2001 Census of Population and Housing. A random selection of dwellings within selected CDs was then screened to assess their usual residents' Indigenous status. Where a dwelling contained one or more Indigenous usual residents aged 15 years or over, up to three Indigenous persons (aged 15 years or over) were randomly selected to participate in the survey.

18 In non-community areas, a significantly lower than expected number of households containing Indigenous usual residents were found after initial screening for Indigenous residents by asking any responsible adult in the household. Additional Collection Districts (CDs) were selected in NSW, Vic., SA and the ACT. Selected dwellings in these CDs were surveyed in a 'top-up' enumeration period from February 2003 to April 2003. The lower than expected number of households identified as containing Indigenous residents may have been due to mobility (persons moving from the CD in which they were enumerated in the Census), and/or non-identification of Indigenous usual residents.

19 After screening about 233,000 households in non-community areas, approximately 2.5% were identified as having an Indigenous usual resident aged 15 years or over, and around 80% of these households then responded to the survey. This response rate does not take into account the 12% of households that were unable to be contacted to establish the Indigenous status of the occupants. In communities, 78% of in-scope households were fully responding, with a further 16% of households yielding some information.

DATA COLLECTION

20 Data collection was undertaken by trained ABS interviewers. Respondents were interviewed personally, with the exception of persons who were too sick or otherwise unable to respond, and those aged 15-17 years for whom consent to interview personally could not be obtained from a parent or guardian. Information about the dwelling, the financial situation of the household, and income for those who had not been selected was collected from a nominated household spokesperson (see Glossary). A total of 9,400 Indigenous persons, or about 1 in 30 of the total Indigenous population aged 15 years or over, from across Australia, responded to the 2002 NATSISS.

21 There were a number of differences between the data collection methods used in communities in remote areas in WA, SA, Qld and the NT, and those used in other geographic areas. In the former, the standard household survey approaches were modified as a result of pre-testing, to take account of language and cultural issues. While question wording and collection methodology were modified in these remote areas, most underlying concepts remained the same across all areas.

22 In discrete communities, and more generally in remote areas, interviews were conducted using a paper questionnaire. In communities, the interviewers were accompanied, wherever possible, by local Indigenous facilitators, who assisted in the conduct and completion of the interviews. The Indigenous facilitators explained the purpose of the survey to respondents, introduced the interviewers, assisted in identifying the usual residents of a household and in locating residents who were not at home, and assisted respondents in understanding questions where necessary.

23 In addition, Community Information Forms (CIFs) were used to collect a limited amount of community level information from the Council Office, such as availability of services and facilities within the community. Well-known community events were identified to assist with defining time frames within the survey.

24 Interviews conducted in non-community, non-remote areas predominantly used a Computer Assisted Interviewing (CAI) questionnaire. CAI involves the use of a notebook computer to record, store, manipulate and transmit the data collected during interviews.

25 Since the survey content in community areas was sometimes different to that collected in non-community areas, not all data items are available for the total Indigenous population. In the data item list, data collected only in community areas (remote areas in WA, SA, Qld and the NT) are denoted by a (C) next to the variable name. (NC) indicates data available from non-community areas only, that is, excluding remote areas in WA, SA, Qld and the NT.

26 A copy of the interview questions is available in the National Aboriginal and Torres Strait Islander Social Survey: Data Reference Package, 2002 (cat. no. 4714.0.55.002) which is available on the ABS web site <www.abs.gov.au>.

WEIGHTING, BENCHMARKING AND ESTIMATION

Weighting

27 Weighting is the process of adjusting results from a sample survey to derive results for the total in scope population. To do this, a 'weight' is allocated to each sample unit for each level of interest e.g. a person and household. The weight is a value which indicates how many population units are represented by the sample unit.

28 The first step in calculating weights for each person or household is to assign an initial weight, which is equal to the inverse of the probability of being selected in the survey. For example, if the probability of a person being selected in the survey was 1 in 30, then the person would have an initial weight of 30 (that is, they would represent 30 people).

29 After calculating the initial weights an adjustment was incorporated into the weighting to account for both the lower than expected number of identified households with Indigenous residents from the screened sample, and for households that were identified as containing Indigenous residents but for which no response was obtained.

Benchmarking

30 These adjusted initial weights were then calibrated to align with independent estimates of the population of interest, referred to as 'benchmarks'. Weights calibrated against population benchmarks ensure that the survey estimates conform to the independently estimated distribution of the population rather than to the distribution within the sample itself. This benchmarking adjusts for any unrepresentativeness in the sample take due either to the randomness of the selections or to non-response within responding households.

31 The survey was benchmarked to the Indigenous estimated resident population aged 15 years or over living in private dwellings in each state and territory, at 31 December 2002. The estimates for 2002 were based on results from the 2001 ABS Census of Population and Housing. The 2002 NATSISS estimates do not (and are not intended to) match estimates for the total Indigenous resident population (which include persons and households living in non-private dwellings, such as hotels and boarding houses) derived from the 2001 Census or from administrative data sources that do cover non-private dwellings.

32 While estimates shown in this publication are based on person weights only, household weights were also constructed using the person weights and calibrated to align with the person-level benchmarks. Data at the household level is available on request (see paragraph 79: 2002 NATSISS products and services).

Estimation

33 Survey estimates of counts of persons are obtained by summing the weights of persons with the characteristic of interest. Estimates for means, such as mean equivalised gross household income, are obtained by multiplying the characteristic of interest with the weight of the respondent, and then deriving the mean of the weighted estimates.

RELIABILITY OF ESTIMATES

34 All sample surveys are subject to error which can be broadly categorised as either sampling error or non-sampling error. Sampling error occurs because only a small proportion of the total population is used to produce estimates that represent the whole population. Sampling error can be reliably measured as it is calculated based on the scientific methods used to design surveys. Non-sampling errors occur when survey processes work less effectively than intended. For example, some people selected for the survey may not respond (non-response); some survey questions may not be clearly understood by the respondent; and occasionally errors can be made in processing data from the survey.

Sampling error

35 Sampling error is the likely difference between the published estimates, derived from a sample of persons, and the value that would have been produced if all persons in scope of the survey had been included. In this publication, estimates with Relative Standard Error (RSE) of 25% to 50% are preceded by an asterisk (e.g. *3.4) to indicate that the estimate should be used with caution. Estimates with RSEs over 50% are indicated by a double asterisk (e.g. **0.6) and should be considered unreliable for most purposes. For more information on sampling error and its impact on interpreting results in this publication refer to the Technical Note.

Non-sampling error

36 One of the main sources of non-sampling error is non-response by persons selected in the survey. Non-response can affect the reliability of results and can introduce bias. The magnitude of any bias depends on the level of non-response and the extent of the difference between the characteristics of those people who responded to the survey and those who did not.

37 To reduce the level and impact of non-response, face-to-face interviews were conducted with respondents; local Indigenous facilitators were employed to assist with interviewing in communities; respondents who initially failed to respond were followed up; and estimates were aligned with population benchmarks to ensure adequate representation of the whole population.

38 As the 2002 NATSISS did not achieve the expected rate of response from screening in non-community areas, there was increased risk of bias in the resultant sample which may not have been adequately compensated for in the weighting of survey results. However, based on analysis of comparable Census characteristics, non-response appears fairly evenly distributed across the analysis variables, indicating that the likelihood of bias in the resulting estimates is small.

39 Other forms of non-sampling error included interviewer error, the self-reported nature of data, and coding and processing errors. Every effort was made to minimise these errors by careful design and testing of questionnaires; intensive training and supervision of interviewers; and extensive editing and quality control procedures at all stages of data processing.

40 An advantage of the Computer Assisted Interviewing (CAI) technology used in conducting interviews in non-community areas for this survey is that it enables edits to be applied as the data are being gathered. The interviewer is alerted immediately if information entered into the computer is either outside the permitted range for that question, or contradictory to information previously recorded during the interview. These edits allow the interviewer to query respondents and resolve issues during the interview. CAI sequencing of questions is also automated such that respondents are asked only relevant questions and only in the appropriate sequence, reducing interviewer sequencing errors.

SEASONAL EFFECTS

41 The estimates in this publication are based on information collected from August 2002 to April 2003, and due to seasonal effects they may not be fully representative of other time periods in the year. For example, the 2002 NATSISS asked questions on involvement in social activities in the three months prior to interview. Involvement in particular social activities may be subject to seasonal variation through the year. Therefore, the 2002 NATSISS results for involvement in social activities could have differed if the survey had been conducted over the whole year or in a different part of the year.

DATA INTERPRETATION

42 Care has been taken to ensure that the results of this survey are as accurate as possible. All interviews were conducted by trained ABS officers. Interviewers were required to demonstrate an awareness of the social and cultural issues affecting Aboriginal and Torres Strait Islander peoples and their communities, and an ability to communicate effectively and sensitively with Indigenous organisations and people. Extensive reference material was developed for use in the field enumeration and intensive training was provided to interviewers in both classroom and on-the-job environments. There remain, however, other factors which may have affected the reliability of results, and for which no specific adjustments can be made. The following factors should be considered when interpreting these estimates:

Information recorded in this survey is essentially 'as reported' by respondents, and hence may differ from that which might be obtained from other sources or by using other collection methodologies. Responses may be affected by imperfect recall or individual interpretation of survey questions.

Some respondents may have provided responses that they felt were expected, rather than those that more accurately reflected their own situation. Every effort has been made to minimise such bias through the development and use of culturally appropriate survey methodology.

Some respondents did not provide one or more required answers. Rather than lose the valuable information provided, these persons were deemed to have responded adequately and were retained in the sample. No attempt was made to deduce or impute when respondents either declined to answer a question or were unable to answer. Rather, such missing values were recorded as 'don't know' or 'not stated'. These 'not known' and 'not stated' categories are not shown in the publication tables. However, the person has been included in the total for most data items. The exception is the equivalised gross household income data item where it was more appropriate to calculate percentages excluding the missing values. Below is a table showing the number and proportion of missing values for key 2002 NATSISS data items.

2002 NATSISS Data Items with a 'Not Known' or 'Not Stated' Category

Estimated number of persons

Proportion

Data item

no.

%

Difficulty communicating with service providers

384

0.1

Level of highest non-school qualification

3,315

1.2

Whether identifies with clan

6,058

2.1

Attendance at cultural event(s) in last 12 months

218

0.1

Whether relatives removed from natural family

56,401

20.0

Whether done any unpaid voluntary work in last 12 months

203

0.1

Self-assessed health status

502

0.2

Smoker status

1,905

0.7

Access to motor vehicles

954

0.3

Whether repairs and maintenance have been carried out in last 12 months

7,066

2.5

Ability to raise emergency money

14,292

5.1

Total persons aged 15 years and over

282,200

100.0

DATA QUALITY

Health

43 Reported information on long-term health conditions was not medically verified, and was not necessarily based on diagnosis by a medical practitioner. There may be some instances of under-reporting as a consequence of respondents being unwilling to talk about a particular subject when interviewed.

44 Results from previous ABS surveys and administrative data collections suggest a tendency for respondents to under-report substance use and alcohol and tobacco consumption levels.

45 The substance use questions in the 2002 NATSISS were based on the National Drug Strategy Household Survey (NDSHS) and had a response rate of over 90%. In non-community areas a voluntary self-enumerated form was used to collect this information whereas in community areas, respondents were required to respond verbally to questions asked by an interviewer. The very low prevalences for substance use reported in community areas has been assumed to be the result of the use of direct questioning in community areas leading to a significant adverse effect on both the level of response and the quality of responses to questions on substance use. For this reason, information on substance use in remote areas is considered to be unreliable and will not be released.

Disability

46 In the 2002 NATSISS there were a number of differences in the questions used to establish disability status and disability type for persons living in remote and non-remote areas. In remote areas respondents were asked fewer screening questions to establish disability status. Respondents in remote areas were not asked about disfigurement/deformity; mental illness requiring help or supervision; conditions that restrict physical activity or physical work (e.g. back problems, migraines); or restriction due to a nervous or emotional condition. The omission of questions on disfigurement/deformity and conditions that restrict physical activity or physical work may have resulted in an underestimate of Indigenous persons with a physical disability in remote areas. In addition, the 2002 NATSISS did not explicitly identify persons in remote areas with a psychological disability (i.e. those who had either a mental illness requiring help or supervision, or a restriction due to a nervous or emotional condition). Some people in remote areas with a psychological disability will have been correctly identified as having a disability (and therefore included in the total of persons with a disability) if they reported that they were receiving medical treatment or taking medication for a restricting health condition, but the type of disability cannot be determined from this information alone.

47 In tables showing disability data from the 2002 NATSISS only, the disability populations are limited to the set of criteria used to identify disability in remote areas. In the table comparing the disability status of Indigenous people in non-remote areas and non-Indigenous people (table 5), more extensive criteria have been used to identify disability.

Law and justice

48 In the 2002 NATSISS, incarceration was broadly defined to include all Indigenous persons aged 15 years or over who had spent any time in jail in the last five years. Efforts were made to exclude persons who had been apprehended and placed in protective custody in a police lock-up owing to public intoxication, other infringements of 'good order', or non-criminal traffic infringements, such as unpaid parking fines. It is acknowledged, however, that in some instances persons incarcerated in this manner could have been included, and cannot be separated from those who were sentenced to serve time in prison or had spent time on remand.

Housing utilisation

49 There is no single standard measure for housing utilisation. However, the 2002 NATSISS has used the Canadian National Occupancy Standard for housing appropriateness. Where this standard cannot be met, households are considered to be overcrowded.

50 The Canadian model is sensitive to both household size and composition and uses the following criteria to assess bedroom requirements:

there should be no more than two persons per bedroom

a household of one unattached individual may reasonably occupy a bed-sit (i.e. have no bedroom)

couples and parents should have a separate bedroom

children less than five years of age of different sexes may reasonably share a bedroom

children five years of age or over of the opposite sex should not share a bedroom

children less than 18 years of age and of the same sex may reasonably share a bedroom

single household members aged 18 years or over should have a separate bedroom.

Equivalised income

51 Equivalence scales are used to adjust the actual incomes of households in a way that enables the analysis of the relative well-being of people living in households of different size and composition. For example, it would be expected that a household comprising two people would normally need more income than a lone-person household if all the people in the two households are to enjoy the same material standard of living. Adopting a per capita analysis would address one aspect of household size difference, but would address neither compositional difference (i.e. the number of adults compared with the number of children) nor the economies derived from living together.

52 When household income is adjusted according to an equivalence scale, the equivalised income can be viewed as an indicator of the economic resources available to a standardised household. For a lone person household, it is equal to income received. For a household comprising more than one person, equivalised income is an indicator of the household income that would be required by a lone person household in order to enjoy the same level of economic wellbeing as the household in question.

53 The equivalence scale used in this publication has been used in recent research work undertaken for the Organisation for Economic Co-operation and Development (OECD) and is referred to as the 'modified OECD' equivalence scale. It is widely accepted among Australian analysts of income distribution.

54 This scale allocates 1.0 point for the first adult (aged 15 years or over) in a household; 0.5 for each additional adult; and 0.3 for each child. Equivalised household income is derived by dividing total household income by the sum of the equivalence points allocated to household members. Therefore, the equivalised income of a household comprising more than one person lies between the total value and the per capita value of its unequivalised income. For example, if a household received combined gross income of $2,100 per week and comprised two adults and two children (combined household equivalence points of 2.1), the equivalised gross household income for each household member would be calculated as $1,000 per week. For more information on the use of equivalence scales, see Household Income and Income Distribution, Australia, 2000-01 (cat. no. 6523.0).

Income quintiles

55 Income quintiles are the groupings that result from ranking all people in the population in ascending order according to their equivalised gross household income, and then dividing the population into five equal groups, each comprising 20% of the population. Income quintiles used in this publication are based on the distribution of equivalised gross household income in the total population as reported in the 2002 GSS. The equivalised gross household income estimates calculated for Indigenous persons from the NATSISS are tabulated and analysed in terms of the quintile boundaries of the equivalised gross household income for the total population of Australia:

Lowest quintile: $0-$264 per week

Second quintile: $265-$426 per week

Third quintile: $427-$611 per week

Fourth quintile: $612-$869 per week

Highest quintile: $870 or more per week.

Persons in low income households

56 If the Indigenous population had the same distribution of household income after the equivalence scale had been applied to adjust for size and compositional differences among households, then we would expect that the income quintiles based on the total population would also divide the Indigenous population into five equal groups each containing 20% of persons. However, since Indigenous equivalised gross household income is considerably lower overall than the corresponding income for the total population, the proportion of Indigenous people in the lowest and second quintiles is in excess of 20% and the proportion in the third and higher quintiles is less than 20%. Income quintiles (and deciles - see following paragraphs) also allow for comparisons of income distribution within the Indigenous populations, for example by state/territory, age and labour force status.

57 After ranking the total population according to equivalised household income, that population can also be divided into ten equal groups or deciles each containing 10% of the population. Previous analysis has shown that households in the lowest income decile tend to have expenditure patterns more in common with higher income households than with other households at the bottom of the income distribution. In the total population, some households report extremely low and even negative incomes because they incur losses in their unincorporated business or have negative returns from their other investments. Other households may under-report income. Some may understate their gross household income because they report income after certain deductions, such as housing costs, have been made. Because of this, it may be reasonably assumed that many households in the lowest income decile are unlikely to be suffering extremely low levels of economic wellbeing, and income distribution analysis may lead to inappropriate conclusions if such households are included. Accordingly, to assist analysis of the circumstances of Indigenous people on low incomes and for comparability with other income analysis, the proportion who fall within the income boundaries of the second and third income deciles (i.e. derived from the 20% of people in the total population with household incomes between the bottom 10% and the bottom 30% of incomes) is presented in this publication as an alternative to the lowest income quintile. For more information on this issue see Household Income and Income Distribution, Australia, 2000-01 (cat. no. 6523.0).

58 The boundaries of the second and third deciles of equivalised gross household income for the total population of Australia based on the 2002 GSS are $214-$338 per week.

Age standardisation

59 Some results presented in this publication have been adjusted to account for differences in the age structure between the Indigenous and non-Indigenous Australian populations, and to allow for meaningful comparison between the 2002 NATSISS and GSS. Selected data items have been age-standardised on the basis that these topics are strongly influenced by age. Age-standardisation has been undertaken using the direct method (see Technical Note).

60 It is important to note that age-standardised estimates are to be used for comparison purposes only. The estimates themselves do not represent any real population parameters. Similarly, the estimates should not be used to quantify the difference between the Indigenous and non-Indigenous populations; they should be used as an indication of difference only.

61 The increased propensity to identify as Indigenous that was observed in the 1996 Census was accounted for by reweighting the 1994 NATSIS data to 1996 Indigenous population benchmarks. There were no major changes in the general age structure of the Indigenous population between 1996 and 2001 and therefore data comparing 1994 NATSIS and 2002 NATSISS results (table 6) have not been age-standardised.

IMPUTATION

62 A small amount of missing data was imputed for the 2002 NATSISS to compensate for errors in the CAI instrument used in non-community areas (see paragraphs 64-66). Imputed data that contribute to results presented in this publication are considered to be fit for the purpose intended. However, caution should be applied when using the following variables which incorporate some imputed data:

education participation - whether currently studying or not studying

full-time/part-time study

type of educational institution attending.

63 Items that incorporate imputed data, but are not displayed in this publication are:

(whether attended) vocational training in last 12 months

type of vocational training undertaken in last 12 months

whether training was done as part of CDEP

whether used training

relevance of training to employment.

64 Due to two errors in the CAI instrument, some respondents were incorrectly sequenced past relevant education questions. The first sequencing error affected respondents who were currently studying, while the second error resulted in an incomplete data set on vocational training. To address these issues, missing education data for the 2002 NATSISS was imputed using Indigenous data from 2001 Census of Population and Housing as a basis for distribution.

65 In CAI interviews, the 733 respondents aged 20-24 years who were not studying full time were sequenced past two questions on whether they were currently studying, and the type of educational institution they were attending. Some 2002 NATSISS data, such as Abstudy receipts, and the 2001 Census distribution of Indigenous persons aged 20-24 years who were not studying full time, were used to calculate the likely proportion of Indigenous persons aged 20-24 years studying either part-time or not at all in the 2002 NATSISS. Similarly, cumulative proportions of persons who were studying part time (by type of educational institution attending) were also calculated. These proportions were used in the 2002 NATSISS imputation model to impute that 4% of the 733 respondents with missing data were studying part-time.

66 The 1,399 respondents who had used employment support services in the 12 months prior to interview were sequenced past four questions on vocational training. In this case these records were retained and the missing information was imputed by replacing each missing value with a value reported by another person (donor records). Donor records were matched to records with missing information on the basis of sex, age and labour force characteristics. As far as possible, the imputed information is an appropriate proxy for the missing data on vocational training.

COMPARABILITY BETWEEN THE 2002 NATSISS AND 1994 NATSIS

67 This publication contains selected results from the 1994 National Aboriginal and Torres Strait Islander Survey (NATSIS). These results are limited to topics where a reasonable level of comparability between the 1994 and 2002 surveys is expected.

68 Understanding the extent to which data from the 2002 NATSISS and the 1994 NATSIS can be compared is essential to interpreting apparent changes over time. While some key data items in the 2002 NATSISS are the same or similar to those in the 1994 NATSIS, there are important differences in sample design and coverage, survey methodology and content, definitions, and classifications, all of which may impact on comparability between the surveys.

69 The main differences between the 1994 and 2002 collections, including field procedures, which may affect the comparability of data presented in this publication are outlined below.

Over-sample in Torres Strait Area to allow for reliable Torres Strait Islander estimates

Prison sample (State/NT)

Enumeration period

April - July 1994

August 2002 - April 2003

Main output units

Person

Person

Family

Household

Household

70 The 1994 NATSIS survey coverage included both private and non-private dwellings as well as, where possible, Indigenous people not living in a dwelling and Indigenous persons in prisons or other correctional facilities. The 2002 NATSISS collected information from persons living in private dwellings only. For this publication, data from the 1994 NATSIS are limited to persons living in private dwellings only, to align with the scope of the 2002 NATSISS.

71 Time-series comparisons between 1994 and 2002 are presented in this publication at the national level and are available at state/territory level on the ABS web site (see paragraph 80). Data from the 1994 NATSIS are not available by remoteness since there is currently no concordance between the geographic structure on which the survey was based (1991 Census of Population and Housing Collection Districts) and the ABS remoteness structure (see Glossary for definitions of remote and non-remote).

COMPARABILITY WITH OTHER DATA SOURCES

72 Data in Appendix 1 indicate that results from the 2002 NATSISS are broadly consistent with other ABS sources. To ensure data comparability with other sources, where possible, question modules from existing surveys were used in the 2002 NATSISS questionnaire. However, due to the number of topics included in this survey, it was not always possible to adopt the full question modules used in other surveys. In addition, some modules were further shortened or omitted in community areas because they were not relevant or not able to be effectively administered within the NATSISS in these areas. Wherever possible, the 2002 NATSISS has used standard ABS 'shortened' question modules. These shortened question modules have been designed to maximise comparability with the full question modules and their use also ensures comparability with other surveys where these shortened modules have been used. Users are referred to the Glossary of this publication for data item definitions and to the National Aboriginal and Torres Strait Islander Social Survey: Data Reference Package, 2002 (cat. no. 4714.0.55.002) available on the ABS web site <www.abs.gov.au>.

73 Results from the 2002 NATSISS may also differ from other ABS surveys collecting information on the same topics because it is a sample survey, and therefore subject to sampling error. Users should take account of the RSEs of survey estimates when making comparisons.

74 Differences may also exist in the scope and/or coverage of the 2002 NATSISS compared to other surveys. For example, the 2002 NATSIS included persons aged 15 years or over, living in private dwellings across Australia. In comparison the GSS included persons aged 18 years or over, living in private dwellings across Australia, but excluding persons living in sparsely settled (i.e. predominantly remote) areas. The Labour Force Survey coverage is different again - including persons aged 15 years or over, living in both private dwellings and non-private dwellings (institutions, hotels, etc.) in all areas of Australia.

75 Further, the 2002 NATSISS was collected over the period August 2002 to April 2003. Data from this survey may be different to other survey results due to differences in reference periods. Underlying trends in the phenomena being measured, seasonal variations and non-seasonal events may all affect comparability.

76 Differences in results can also occur as a result of different collection methodologies. This is often evident in comparisons of similar data items from different ABS collections where, after taking account of definitional and scope differences and sampling error, residual differences remain. These differences often relate to the mode of collection, such as whether data are collected by an interviewer or self-enumerated by the respondent, whether the data are collected from the person themselves or from a proxy respondent, and the level of experience of interviewers undertaking the data collection. Differences may also result from the context in which questions are asked i.e. the relative ordering of questions in the interview. Because of the nature of such differences between statistical collections the impacts on data are difficult to quantify. As a result every effort is made to minimise such differences.

77 The proportions of people reporting in NATSISS as having obtained a certificate or diploma non-school qualification, and those obtaining any non-school qualification are similar to the measures derived from the 2001 ABS Survey of Education and Training. The much lower proportion of people reported in the Census (14%) as having obtained a certificate or diploma compared to the proportion reporting in NATSIS (22%) is expected to have resulted largely as a consequence of Census reporting being undertaken by people on behalf of those being enumerated. Respondents in discrete Indigenous communities may be answering Census interviewer questions about the educational attainment of several other household members and may not be aware of the qualifications obtained by those people. Similarly, in households completing standard Census forms, a household member may complete details on behalf of another person in the household and be unaware of the qualifications obtained by those people.

78 More information on the 1994 NATSIS and 2002 GSS can be found in publications listed in paragraph 89.

2002 NATSISS PRODUCTS AND SERVICES

79 Below is information describing the range of data to be made available from the 2002 National Aboriginal and Torres Strait Islander Social Survey both in published form and on request. The program of publications and other releases may be subject to change. Products available on the ABS web site <www.abs.gov.au> are indicated accordingly. To request any of these products or to obtain further information on the products please contact the officer noted in the front of this publication.

State/territory tabulations

80 Tabulations for each state and territory to be released concurrently with this publication consist of a subset of the tables presented in this publication. These tables have been customised depending on the magnitude of the Relative Standard Errors (RSEs). These sets of tables are available in spreadsheet format on the ABS web site, released as National Aboriginal and Torres Strait Islander Social Survey, state/territory, catalogue numbers 4714.1.55.001 to 4714.8.55.001.

Microdata

81 For users who wish to undertake more detailed analysis of the survey data it is expected, subject to approval by the Australian Statistician, that microdata from the 2002 NATSISS will be released in the form of an expanded confidentialised unit record file (CURF). The expanded CURF will only be available via the Remote Access Data Laboratory (RADL), which is a secure Internet-based data query service. This service will be accompanied by an Information Paper describing the content of this CURF and it is expected to be available in August 2004.

82 Up-to-date information on the ABS RADL service, including information on pricing, 'Applications and Undertakings', and a training manual outlining obligations and responsibilities when accessing ABS microdata, is available on the ABS web site <www.abs.gov.au - Products and Services - Access to ABS CURFs>. Those wishing to access 2002 NATSISS microdata should contact the officer noted at the front of this publication.

83 A package containing sample copies of the 2002 NATSISS questionnaire and prompt cards, together with a list of the output data items from the survey is available free-of-charge on the ABS web site or may be requested from the contact officer listed at the front of this publication. This package has been released as National Aboriginal and Torres Strait Islander Social Survey: Data Reference Package, 2002, (cat. no. 4714.0.55.002).

Other products and services

84 Special tabulations of 2002 NATSISS data are available on request and for a fee. Subject to confidentiality and sampling variability constraints, tabulations can be produced from the survey incorporating data items, populations and geographic areas selected to meet individual requirements. These can be provided in printed or electronic form.

85 A summary booklet highlighting key results without the complex statistical analysis will be prepared for wide distribution to Indigenous communities, organisations and schools.

86 The ABS is still investigating the feasibility of producing state/territory mapping products for the 2002 NATSISS, as were produced for the 1994 NATSIS.

87 The ABS National Centre for Aboriginal and Torres Strait Islander Statistics (NCATSIS) will conduct a series of seminars with key stakeholders to publicise 2002 NATSISS results.

88 Detailed analysis of specific areas of concern for Aboriginal and Torres Strait Islander peoples will be undertaken by ABS using 2002 NATSISS data and published either in a series of thematic publications or as articles in various compendium style publications. This analysis will explore the interaction between social dimensions collected in the 2002 NATSISS, provide insight into variations in patterns of socioeconomic outcomes among Indigenous peoples, and make comparisons with the total Australian population using data from the GSS.

90 Current publications and other products released by the ABS are listed in the Catalogue of Publications and Products (cat. no. 1101.0). The Catalogue is available from any ABS office or the ABS web site. The ABS also issues a daily Release Advice on the web site which details products to be released in the week ahead.

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